Pump unit

ABSTRACT

A pump unit for use in a tank adapted to be filled with a hydraulic fluid to a predetermined fluid level is provided and members suspend the pump and motor assembly in the fluid tank normally below the fluid level. These suspending members are attached at spaced points to means carried by the walls of the tank and the attachment means include vibration dampening members. A valve unit is provided in the tank below a removable tank cover and above the predetermined fluid level for the tank.

United States Patent Carl Oscar Torsten Montelius Djursholm, Sweden [21]Appl. No 844,395

(22] Filed July 24, 1969 [45] Patented July 20, 1971 [73] AssigneeAktiebolaget lmo-lndustri Stockholm, Sweden [72] inventor s4 PUMP UNIT 4Claims, 2 Drawing Figs.

[52] 11.5. CI 222/333 [51] Int. Cl ..F04d 13/02, F04c 15/00 [50] FieldolSearch 222/333,

References Cited UNITED STATES PATENTS 2,139,370 12/1938 Lauer etal2,174,348 9/1939 Damond 222/333 X 2,319,934 5/1943 Korte et a1. 103/873,090,318 6/1960 Jeep et al..,. 103/87 3,136,259 6/1964 Bood 103/873,172,572 3/1965 Brown et al 222/109 3,193,151 7/1965 Jeep et a1 222/1803,369,715 2/1968 Carter 222/333 Primary Examiner-Lloyd L. King AssistantExaminerEdwin D. Grant Alt0rney-Oldham and Oldham ABSTRACT: A pump unitfor use in a tank adapted to be filled with a hydraulic fluid to apredetermined fluid level is provided and members suspend the pump andmotor assembly in the fluid tank normally below the fluid level. Thesesuspending members are attached at spaced points to means carried by thewalls of the tank and the attachment means include vibration dampeningmembers. A valve unit is provided in the tank below a removable tankcover and above the predetermined fluid level for the tank.

PUMP UNIT The present invention relates to a pump unit having a pump andassociated motor immersed in liquid.

The use in hydraulic systems of pumps and motor units completelyimmersed in the oil tank of the system is becoming more and more usual.This procedure has been found to present significant advantages,particularly since the construction of both the pumpand the motor can besimplified to a considerable extent.

One problem associated with this system is, however, one of mounting theunit in the oil tank so that vibrations from the unit are nottransmitted to the surroundings to a disturbing extent. The unit isnormally mounted to the bottom of the tank. This enables rubbervibration absorbers to be mounted between the unit and the tank bottom.The disadvantage with this solution, however, is that rubber is attackedby the majority of hydraulic oils, and hence the effective life time ofthe vibration absorbers is short. It is also possible to place the unitat' the bottom of the tank without vibration absorbers therebetween, andto mount the vibration absorbers between the tank and the foundation.Vibration of the actual tank to a disturbing extent is prevented in thisinstance by using a relatively thick plate in the actual tank or partsthereof. This solution is not completely satisfactory either.

In addition, irrespective of the manner in which the vibrations areabsorbed, the method of mounting the unit on the tank bottom usedhitherto incur readily perceived difficulties when the unit must bedismantled for inspection, repair or maintenance.

The object of the present invention is to provide an arrangement wherebya pump unit can be mounted in an oil tank in such a manner that theaforementioned difficulties are circumvented. Damping of vibrations inaccordance with the invention canbe achieved in a very simple manner,and installation and dismantling of the unit is rendered much simpler.

ln accordance with the present invention, the pump unit is suspended inthe upper portion of the tank above the level of the liquid. The pumpunit can thus be suspended from attachment points mounted to orfastenedwith the walls of the tank with the vibration damping means positionedbetween the attachments and the walls, so that the vibration dampers aresituated above the level of the liquid and not subjected to attacktherefrom. By securing the unit in this way it is relatively easy toremove from the tank.

Associated with the hydraulic system is a control valve to an inlet ofwhich a line extends from the outlet of the pump passes. Furthermore,lines pass from other openings at the valve to the hydraulic operatingdevices in the system and a return line which opens into the tank forreturn of oil thereto. This valve can to advantage be placed on supportmeans within the tank, suitably with a vibration damping meanspositioned therebetween. To prevent vibrations from being transmittedfrom the unit to the valve through the line, the line may consist whollyor partially of a hose. In a suitable embodiment, a substantiallyvertical hose is attached from the pump outlet to an elbow tube, fromwhich an essentially horizontal hose extends to the valve.

The invention will now be described with reference to the accompanyingdrawings, in which:

FIG. 1 shows an oil tank in longitudinal section provided with a unitmounted therein in accordance with the invention,

F IG. 2 shows a cross section of the tank.

ln FIGS. 1 and 2 there is shown an oil tank 1, filled with oil duringoperation to a level which varies between levels a and b. The tank isprovided with a cover plate 2 which can be fastened in a suitable mannerto the upper surface of the tank. A unit consisting of a pump 4 and amotor 5 is arranged in the tank so that during operation at least thelarger portion of the unit is immersed in the oil (below level b). Theconstruction and design of the pump and motor are not within the purviewof the present invention and will not be described in detail. The pump,for instance, may be an [mo-pump of well-known design and the motor aknown type of electric motor, which are combined to form a unit.

In the embodiment of FIGS. 1 and 2, the unit 4, 5 is suspended by meansof three steel wire ropes 6, 7, 8 which are attached to suitableattachment means on the unit and to beams 9, 10 in the tank by means ofconical, cup-shaped vibration dampers ll, l2, 13 made of rubber.

The outlet of the pump 4 is shown at 20. Extending from the outlet is apressure hose 21, extending up to a metal elbow pipe 23, from which ashort hose 24 extends to an inlet at a control valve 25, from whichlines depart to the hydraulic operating devices. The valve 25 isattached to the beam 10 and a beam 26, with an elastic pad member 27, 28therebetween. A return line 29 passes from the valve to the oil tank.

The vibration damping means ll, l2, 13, which are attached so that theydo not contact the oil, effectively dampen all transmission ofvibrations from the unit to the tank. The hoses 21, 24 serve to preventtransmission of vibrations from the unit to the valve 25. If theresilient support pad 27, 28 alone is sufficient to dampen vibration,the hoses can be replaced with rigid conduit.

I claim:

1. A pump unit comprising a fluid tank adapted to be filled withhydraulic fluid to a predetermined fluid level, a detachable cover forsaid tank, suspending members attached at spaced points to attachmentmembers carried by the walls of said tank below said cover and abovesaid fluid level by means of vibration dampening members, a pump andmotor assembly suspended in said fluid tank nonnally below said fluidlevel only by means of said suspending members, and a valve unit mountedin said tank below saidcover and above said liquid level and having afluid inlet operatively connected to a fluid outlet of the pump by meansincluding a conduit.

2. A pump unit as in claim I, where said conduit is flexible, andresilient means support said valve unit on a beam carried by the tankwalls.

3. A pump unit as in claim I, where said suspending mem- I bers comprisewire ropes.

4. A pump unit as in claim 1, where a return line extends between saidvalve unit and the lower portion of said tank for return of fluidthereto.

1. A pump unit comprising a fluid tank adapted to be filled withhydraulic fluid to a predetermined fluid level, a detachable cover forsaid tank, suspending members attached at spaced points to attachmentmembers carried by the walls of said tank below said cover and abovesaid fluid level by means of vibration dampening members, a pump andmotor assembly suspended in said fluid tank normally below said fluidlevel only by means of said suspending members, and a valve unit mountedin said tank below said cover and above said liquid level and having afluid inlet operatively connected to a fluid outlet of the pump by meansincluding a conduit.
 2. A pump unit as in claim 1, where said conduit isflexible, and resilient means support said valve unit on a beam carriedby the tank walls.
 3. A pump unit as in claim 1, where said suspendingmembers comprise wire ropes.
 4. A pump unit as in claim 1, where areturn line extends between said valve unit and the lower portion ofsaid tank for return of fluid thereto.